The Andhra Pradesh health department has completed one round of sero surveillance in all 13 districts, aimed at identifying the presence of anitbodies for Coronavirus in the state population.
"Sero surveillance provides estimates of antibody levels against infectious diseases and is considered the gold standard for measuring population immunity due to past infection or vaccination," said an official.
Conducted in two phases, the first phase involved testing 3,500 people each in the districts of East Godavari, Krishna, Nellore and Ananthapur from August 5 to 15.
In the second phase, 5,000 people each have been tested in the districts of Srikakulam, Vizinagarm, Visakhapatnam, West Godavari, Guntur, Prakasham, Kadapa, Chittoor and Kurnool from August 26 to 31.
"Sero surveys will provide information on what proportion of the population may have acquired immunity to Covid and be able to track this over time," he said.
Following the first round survey, the department has identified that the high-risk population stands at 20 per cent.
"The results help us in understanding the spread of infection and planning of hospital and other Covid-related infrastructure, targeting our tests to yield better results," he added.
Andhra Pradesh registered 10,175 new Covid positive cases on Thursday, raising the state's tally to 5.37 lakh.